The strength of domestic graphite (NG-CT-01) is studied by experiments. Considering the dispersion of graphite material strength, samples are cut with different positions, directions, and blocks. The tensile, compressive, and flexural strength of the material are tested according to the national standards. Compressive stress is based on the equivalent tensile stress that appears in the evaluation of the stress on graphite, and the graphite safety evaluation of the data is determined by the tensile strength of the experiment. Therefore, the minimum strength is given based on the calculation of the tensile strength for the measured data. For graphite strength safety evaluation, the graphite strength Weibull distribution must be known. By using the maximum likelihood method, two-parameter Weibull distribution parameters are fitted with the tensile strength of the experimental data by means of the software of Weibull++7. Experimental data are fitted by two-parameter Weibull distribution. The estimated Weibull parameters are modified by following the German HTGR design specifications KTA-3232 HTR Ceramic Pressure Vessels Internals(1992).It provides the basis parameters for the future validation static and dynamic experiments for HTR-PM projects. After comparing the experimental results, the conclusion could be drawn out that the graphite strength parameters have been improved based on the original data, and the parameters are able to basically meet the technical requirements for the structural and seismic engineering verification tests.